Does double clicking .jar files work on all OS's? I could just keep update.jar and game.jar seperate, and if there is an update when you run game.jar it could just say "update found, run update.jar". Then I wouldn't need bat files or a private JVM.

absolutely notpc's who have java installedpc's who have the version of java installed that you needpc's on which dbl clicking a jar actually worksand pc's which are owned by people know you can dbl click jars and dont mind java

so no, its very unlikely that it will work any other way

about the size: well depends on your game; our's will be like 700mb - at that size, a 70mb VM doesnt even matter

If your game is small but you can catch the interest of users enough, you can make them install a propper Java.(So a well made propaganda site with nice screenshots will help)But this wont work for like a small Packman clone.

Packaging the JVM with the game really only makes sense in large Games, not for a 2 MB casual game.

Make it easy for people to get to the official Java Download link.If they already bothered to to download an installer/exe (so not just a browsergame) they might not bother to download/install Oracles JVM.

I think Minecraft also helped push the ecosystem of normal gamers installing and accepting Java.So thanks for that.

I think getting users to run a fitting JVM ist less the issue than providing them a convenient way to start the game itself.(exe, maybe even with an installer/desktop icon)

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